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Immune System Problems in the GSD and Other Breeds
by Fred Lanting
Copyright September, 2006 -
The German Shepherd Dog is a very popular breed. In fact, it is Number One worldwide although in the U.S. it ranks much lower partly because of AKC clubs' non-adherence to the international Standards - usually in the AKC top ten, though. As a result of there being so many GSDs, veterinarians and others typically see more cases of most disorders than they do in other breeds. Popularity has its drawbacks, and undeserved notoriety is one of them. Take the incidence of dog bites, for example. Many breeds have far more of a tendency to bite people than does the GSD, although they don't get the same "press" (publicity). Min-Pins, Skye Terriers, American Cockers, Chows, and many others will sink their fangs in you more readily and with less provocation. But the popularity of Shepherds, Rottweilers, and a couple others is their downfall.
Of course, not all popular breeds are involved in as many biting incidents. You have to travel a long road to find a Golden Retriever that has ever bitten a person, and Labs have an intermediate incidence compared to others of its size. Nor do big dogs bite more (although perhaps with more damage) - the mastino types are usually placid, while the feists like Chihuahua/terrier-types and mixes give credence to their name and the word "feisty".
That was just an example of generalizations that abound in the dog world. Some are unfounded; others have a basis in statistical facts. Another example is the incidence of hip dysplasia. Rottweilers and American Pit-Bull Terriers may have nearly the same percentage and typical severity of HD as in the GSD, but the Shepherd is almost unique among breeds in that HD causes more discomfort and lameness than same degree of looseness in the joints of the more stoic breeds with some bulldog heritage.
Another problem seen quite frequently in the GSD is the deficient immune system syndrome (a syndrome is a collection of symptoms). It is characteristic of this problem to manifest itself in one dog in a certain way, and in another dog in a different way, a little like a pleiotropic trait. Some evidences are so slight that many owners and vets miss or don't guess at the underlying cause. This leads the doctor to wrongly prescribe a certain medicine or none at all, and the breeder to go ahead and breed a covertly defective dog that should not be mated. Further complicating the matter, and preventing as much progress as could be had, is the subclinical nature (a lack of, or hardly-noticeable, signs. Many intermittent or mild complaints that owners have are not identified as related to the dog's immune system, and others have taken years of badgering by breeders before the veterinary community has acknowledged what breeders had known all along. So you will find some disagreement in some of what I will present in the following material. I don't want to just list a table of disorders under the subject heading, but you might want to do that for yourself. Let's take a look at some of those immune-mediated disorders after a few more words about the general subject.
The GSD has more than its "fair share" of immune-related problems, and they appear in the intestines, eyes, skin, and other places. The breed has many individuals with a deficiency of a particular immunoglobulin called IgA, and this genetic defect may be very close on the chromosome to genes controlling general immune problems.
Autoimmune disorders
The dog's "Defense Department" has a number of soldiers: antibodies, immunoglobulins, specialized cells, and more. Some vaccine ingredients, adjuvants, or carriers have been known to cause an over-reaction by this army and result in an autoimmune situation in which the body also attacks its own cells. A recent vaccination development called "recombinant vaccine", helps avoid bad reactions to vaccines or the medium in which they are cultured or carried into the blood system, but is not effective against parvo. Nowadays, the over-reaction is more often a matter of genetics than any stimulus from vaccine components.
The German Shepherd Dog is at risk for a number of immune system abnormalities, and while not all have been directly linked to immune suppression, there is great suspicion of a connection with most of them. We have seen such problems in the breed as pannus (chronic superficial keratitis), corneal dystrophies, and plasmacytic conjunctivitis in the eye; lupus and anal furunculosis in the outer integument; and plasmacytic colitis in the gastrointestinal tract; these we suspect are related to autoimmunity. The various components and functions of many glands and chemicals in the normal body are lumped together to refer to their joint action of protection, and given the name "immune response" or "immune system". It involves such things as T cells, phagocytes, white blood cells, antibodies (immunoglobulins), complement proteins, and others. Together, their job is that of a second line of defense against antigens and other threatening "foreigners"; the skin, mucous membranes, and stomach acid are some of the first-line defense mechanisms that bodies have, and if something harmful gets past the frontline troops, the interior guard must go to work.
Invading organisms may be viral, bacterial, parasitic, fungal, and may come into the body via puncture, swallowed foreign objects, impurities in eaten material, absorption through the skin, intake by the lungs, or other routes. This second line of defense even goes after waste generated in the cells, or abnormal cells which if left alone could become cancerous. To do this, the soldiers must be able to recognize the enemy, and do so by chemical means, such as "seeing" if the projections on the suspects fit like jigsaw pieces into receptors carried by the troops. If so, they attempt to neutralize by putting chemical handcuffs or a half-nelson on those invaders until they can dispose of them. Some of the home guard, macrophages, actually "eat" bacteria; some poke holes in the invaders or mark them for other cells to eat or destroy. When such interactions occur, the guard is stimulated to call for reinforcements (multiply rapidly) to search for more of the invaders' ilk. Our B-lymphocytes have antibody protein molecules on their cell surfaces that recognize the foreign molecule called an antigen. One result of this encounter is that these B "white blood cells" become antibody factories called plasma cells, and can turn out their product for many years to come. Thus, some diseases are warded off the rest of our lives because our bodies continue to have patrolling soldiers that can recognize them. The other type of defender lymphocyte is the T cell. They directly kill "bad" cells without using antibodies. Besides killer T cells there are helper T cells and suppressor T cells; the latter call off the attack so the white blood cells (lymphocytes) don't get carried away over-multiplying (hopefully!) or that would present other problems.
One hitch in the war machinery is that some lymphocytes get confused and mistake normal body (called "self") proteins for the "bad guys". If "Self" doesn't kill off these errant traitors, as normally happens in the embryo and very young individual, we have what is called an "autoimmune" situation. An oversimplification would be to say that the body is "allergic to itself". In any case, the body uses the home guard to attack and possibly destroy part of itself (its self). Such a defect can affect immune response all through the body. It is possible that this is happening in pannus, "allergies", lick granuloma, and a number of other problems in your or my dog. In human AIDS, all the active helper T cells are destroyed, so the body no longer has adequate defenses against any and all antigens. In most disorders, only one or two pathways are affected, so a problem may show up as an itch, skin blisters, hemolytic anemia, a corneal defect, rheumatoid arthritis, or something else in one or more organs.
Demodex: One of the most easily identified immune-mediated problems is demodectic mange. To distinguish between this and the purely contagious sarcoptic mange, see some of my other articles or buy my book on the GSD. The demodex mite is ever-present on nearly all dogs and humans, but doesn't cause a problem unless the host is weakened by something, especially another immune system related disease or stress. It is widely believed that stress of various kinds, whether of a genetic origin such as a very nervous temperament, or either a genetic or acquired immunodeficiency disease that suppresses T cell function in the immune defense system, may be the major factor in an outbreak of symptoms such as demodecosis in a dog. With lowered cell mediated immunity, the individual reacts adversely not only to the mite and its toxins, but also to the presence of other microbes and antigens. "Neutering" reduces stress in the individual and helps brake the spread in the gene pool. A bitch in estrus is in the highest state of systemic stress that any dog normally encounters, outside of severe trauma and shock. Often enough, demodecosis is concurrent with another immune-related defect. If your dog has demodectic mange, look for another condition that should be treated at the same time. Is there a history of subclinical pancreatitis? Has there been recent surgery or other physical or emotional trauma? Any exposure to debilitating diseases? Even the minor stress of teething may be sufficient to tip the balance and encourage sudden proliferation of mites and their symptoms. Very healthy dogs rarely show symptoms even when exposed intentionally by clinical transmission of the mites. Stress (such as illness) seems to "awaken" the mites. Combating demodecosis is largely a matter of curing or controlling the dog's other ills, both physical and psychological. Use of steroids is contraindicated because they compromise the dog's immune defense. See my "Total German Shepherd Dog" book for more detail on this topic.
Pancreatitis: In its chronic, subclinical, or often-undiagnosed mode, exocrine pancreatic insufficiency (EPI or PI) is fairly common in German Shepherd Dogs of certain bloodlines. It has even been identified with demodectic mange, possibly because during the stress of the dog's affected digestion, its body is less able to immunologically suppress the proliferation of the mange mites. Supplementation with vitamin A and pancreatic enzymes should be supervised by a veterinarian who is knowledgeable in this area and has been made aware of the genetic nature of the problem in certain lines of our breed. The occurrence in pancreatic insufficiency among German-line dogs in the U.S. has increased since the 1970s, but I believe there are a couple of different reasons for this, if it is an accurate observation.
Malabsorption (poor digestion and poor stool condition) are frequently seen in the GSD, and in my experience, has been more so in the heavily linebred typical lines in American-bred dogs since the 1970s. EPI is one of the conditions that can contribute to the malabsorption syndrome. The symptoms can be exacerbated by physical or emotional stress, change of food, and other things. I suspect that dogs with subclinical weakness in immune systems or pancreatic function may be most likely to show these reactions. With EPI, the fur often becomes dry and brittle, and even lost to some extent, and Staphylococcus infection scabs may appear on the skin because the compromised immune system doesn't allow the dog to fight off the infection. The symptoms of EPI mostly show up when the TLi value is down (Trypsin like immunoreactivity test). So there seems to be a possible connection, with insufficient pancreatic function and other resistance" all being tied to the immune system.
A dog with the sub-acute form of pancreatitis may exhibit coprophagy, which means he eats his own (or others') stools. It may be that he smells the undigested fats and carbohydrates and instinctively consumes it as food to give those nutrients "another chance." Often, the addition of liver to a low fat diet and daily administration of enzyme powder or capsules, or regular supplementation with ground pancreas if you are lucky enough to get some from a nearby slaughterhouse, will bring the condition under control or at least improve it. Researchers at Tulane University found that a commercially available enzyme supplement could improve blood analysis, neonatal vitality, digestion, and general health. The manufacturers of Viokase™, a dried raw pancreatic enzyme brand, have shown that supplement/medicine to be effective in combating nonspecific diarrhea as well as German Shepherd Dog subclinical pancreatitis. The juvenile-onset generalized demodecosis often has a spontaneous semi-remission because of better stress management.
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Fred Lanting is an internationally respected show judge, approved by many registries as an all-breed judge, has judged numerous countries’ Sieger Shows and Landesgruppen events, and has many years experience with SV. He presents seminars and consults worldwide on such topics as Gait-&-Structure, HD and Other Orthopedic Disorders, Anatomy, Training Techniques, and The GSD. He conducts annual non-profit sightseeing tours of Europe, centered on the Sieger Show (biggest breed show in the world) and BSP.
All Things Canine -- consulting division, Willow Wood Services Phone: 256-498-3319 Fax: 256-498-3311 E-mail mr.gsd@netscape.com
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